A lidar system includes a photonic chip including a light source and a transmit beam coupler to provide an output signal for transmission. The output signal is a frequency modulated continuous wave (FMCW) signal. A transmit beam steering device transmits the output signal from the transmit beam coupler of the photonic chip. A receive beam steering device obtains a reflection of the output signal by a target and provides the reflection as a received signal to a receive beam coupler of the photonic chip. The photonic chip, the transmit beam steering device, and the receive beam steering device are heterogeneously integrated into an optical engine.

Photonic devices are disclosed including a first cladding layer, a first electrical contact comprising a first lead coupled to a first dielectric portion, a second electrical contact comprising a second lead coupled to a second dielectric portion, a waveguide structure comprising a slab layer comprising a first material, and a second cladding layer. The slab layer may be coupled to the first dielectric portion of the first electrical contact and the second dielectric portion of the second electrical contact. The first dielectric portion and the second dielectric portion may have a dielectric constant greater than a dielectric constant of the first material.

Conventional systems use a polarization-maintaining fiber (PMF) in order to maintain the light in the same polarization between a laser light source and an optical waveguide on a photonic integrated circuit (PIC). A polarization controller may be provided at an input port of the PIC configured for the manipulation of one or both of the TE.sub.0 and TM.sub.0 polarized light modes. The polarization controller may include a polarization beam splitter/rotator (PBSR), including a plurality of phase tuners and a plurality of couplers which are coupled together by waveguides, all of which are integrated in a device layer on the PIC.

Conventional systems use a polarization-maintaining fiber (PMF) in order to maintain the light in the same polarization between a laser light source and an optical waveguide on a photonic integrated circuit (PIC). A polarization controller may be provided at an input port of the PIC configured for the manipulation of one or both of the TE.sub.0 and TM.sub.0 polarized light modes. The polarization controller may include a polarization beam splitter/rotator (PBSR), including a plurality of phase tuners and a plurality of couplers which are coupled together by waveguides, all of which are integrated in a device layer on the PIC.

An optical interposer for providing optimal optical coupling between an optical transceiver interface and an external optical interface includes an interposer photonic integrated circuit (PIC) operably configured to couple an optical signal between the optical transceiver interface and the external optical interface, one or more waveguide based optical devices operably integrated on a common substrate and one or more of interposer input/output (I/O) channels operably configured with the optical transceiver interface and the external optical interface.

A single-ended output circulator includes a three-core optical fiber head having first, second, and third optical fiber cores; a walk-off crystal having a first surface facing towards the second end of the three-core optical fiber head tube and a second surface facing away from the second end of the three-core optical fiber head tube; a plurality of half-wave plates each having a first surface coupled to the second surface of the walk-off crystal and a second surface facing away from the second surface of the walk-off crystal; a collimating lens having a first end and a second end; a reflection mirror configured to reflect light beams from the collimating lens; an optical prism between the collimating lens and the reflection mirror and configured to transmit a light beam along a propagation direction according to a polarization direction of the light beam; and a polarization rotator.

A polarizer for a waveguide, comprising a main body for transmitting an electromagnetic wave, a first delay member being provided in the main body. A second delay member arranged downstream of the first delay member in the working direction (A) of the electromagnetic wave is provided in the main body, and the polarization axis (P.sub.2) of the second delay member is rotated relative to the polarization axis (P.sub.1) of the first delay member by a delay angle (β).

Example polarization splitter and rotator devices are described. In one example, an optical apparatus includes a splitter configured to split a light signal into a first signal having a first polarization and a second signal having a second polarization, a polarization rotator configured to rotate the second polarization of the second signal into a third polarization, and a polarization mode converter configured to convert the third polarization of the second signal into the first polarization. In certain aspects of the embodiments, the splitter can be a curved multi-mode inference (MMI) polarization splitter, and the polarization rotator comprises input and output ports, with the output port being wider than the input port. The polarization mode converter can be an asymmetrical waveguide taper mode converter. The devices described herein can overcome the deficiencies of conventional devices and provide low insertion loss, flat and/or wide wavelength response, high fabrication tolerance, and compact size.

Embodiments herein describe reverse biasing one or more PIN junctions formed in at least one layer of a PSR. The resulting electric fields in the PIN junctions overlap with the optical path of the optical signal and sweep away photo-generated hole-electron free carriers away. That is, the electric fields in the PIN junctions remove the free carriers from the path of the optical signal and reduces the population of the free carriers, thereby mitigating the negative impact of free-carrier absorption (FCA).

Techniques for reducing interference with sensor (light) signals and measurement in polarimetric fiber optic sensors from undesired effects of current and vibrations on light signals carried in fiber optic cables are presented. A sensor system comprises a first depolarizer associated with a fiber optic cable and in proximity to a light source that provides a light signal to such cable. First depolarizer depolarizes the light signal to produce a first depolarized light signal output to another portion of the fiber optic cable that can be wrapped around or associated with a conductor cable or ground cable. To reduce undesired polarizing effects on the first depolarized light signal due to current or vibrations from the conductor cable or ground cable, the system comprises a second depolarizer that depolarizes the (re)polarized light signal to produce a second depolarized light signal suitable for use in sensing current or voltage after additional processing.